% Regression matrix for whitespace-insensitive command chaining (adopted in
% v2.6.0; ISSUE_BACKLOG.md #1). Asserts that a space, line break, or comment
% between cooperating gckanbun commands produces the SAME box width as the
% adjacent form, i.e. the \peek_remove_spaces:n lookahead neutralises the space.
%
% Part of the LuaLaTeX regression gate (`make check`). See FIX_WORKLOG.md (#1).
%
% Engine: LuaLaTeX. A width mismatch raises \PackageError (fails make check).
\documentclass[luatex,fontsize=9pt,paper=a4]{jlreq}
\usepackage{gckanbun,lltjext}

\newsavebox{\EdgeA}
\newsavebox{\EdgeB}
\newcommand{\AssertSameWidth}[3]{%
  \sbox{\EdgeA}{#2}%
  \sbox{\EdgeB}{#3}%
  \ifdim\dimexpr\wd\EdgeA-\wd\EdgeB\relax<0pt
    \dimen0=\dimexpr\wd\EdgeB-\wd\EdgeA\relax
  \else
    \dimen0=\dimexpr\wd\EdgeA-\wd\EdgeB\relax
  \fi
  \ifdim\dimen0<0.01pt
    \typeout{GCK-WS PASS #1: \the\wd\EdgeA = \the\wd\EdgeB}%
  \else
    \PackageError{gckanbun-edge-test-whitespace}{Width mismatch in #1:
      \the\wd\EdgeA\space vs \the\wd\EdgeB}{Adjacent and space-separated forms
      should have equal widths once whitespace is ignored.}%
  \fi
}

\begin{document}

\section*{Whitespace-insensitivity assertions (\#1)}

% group ruby + return mark
\AssertSameWidth{groupruby-kaeri-space}
  {\グ振り{読}{よ}\返り{レ}書}
  {\グ振り{読}{よ} \返り{レ}書}

% mono ruby + return mark
\AssertSameWidth{ruby-kaeri-space}
  {\振り{天}{てん}\返り{レ}地}
  {\振り{天}{てん} \返り{レ}地}

% ruby + okurigana
\AssertSameWidth{ruby-okuri-space}
  {\振り{行}{ゆ}\送り{ク}}
  {\振り{行}{ゆ} \送り{ク}}

% okurigana + return mark
\AssertSameWidth{okuri-kaeri-space}
  {\振り{読}{よ}\送り{ム}\返り{レ}}
  {\振り{読}{よ}\送り{ム} \返り{レ}}

% group ruby + okurigana
\AssertSameWidth{groupruby-okuri-space}
  {\グ振り{所以}{ゆえん}\送り{ナリ}}
  {\グ振り{所以}{ゆえん} \送り{ナリ}}

% newline (single line break = space) between ruby and return mark
\AssertSameWidth{ruby-kaeri-newline}
  {\振り{天}{てん}\返り{レ}地}
  {\振り{天}{てん}
   \返り{レ}地}

All whitespace assertions passed.

\end{document}